About Light Therapy for Sore Joints & Muscles

Clinical Success in Joint & Muscle Pain Relief

Light therapy means using the energy contained in light to stimulate the body’s own biochemical processes to reduce pain and inflammation in injured tissues. It is also called low-level light therapy, photon therapy or phototherapy.

Clinical studies have examined the effectiveness of light therapy for a wide range of treatments and patients.  In general, their results have confirmed the success experienced by practitioners in over 25 years of actual use with patients.

A significant amount of research supports the effectiveness of light therapy for at least temporary relief of minor muscle and joint pain associated with musculoskeletal injuries caused by sports or daily activities, 1-8 and sub-acute or chronic pain such as from osteoarthritis. 9-11

Physicians, physical therapists and trainers who use the LumiWave® device have their own success stories treating musculoskeletal injuries in amateur and professional athletes.

How Light Therapy Works

Scientists in animal physiology continue to study exactly how light therapy works to relieve pain. The evidence so far suggests that light therapy stimulates the body’s own biochemical processes in one or both of the two ways described below. Very possibly, other physiological mechanisms are also involved that remain poorly understood.

1. Inhibition of Pain Signals.  Light energy appears to act on specific nerve fibers involved in the “slow conduction” of pain signals.12-14 Researchers think that light penetrating to the nerves may stimulate the body to produce endorphins, which are naturally occurring proteins capable of blocking the sensation of pain.15

2. Release of Nitric Oxide.  Light energy also appears to stimulate the body to release nitric oxide. This is a naturally-occurring chemical in the body whose molecules are thought to signal the body to produce numerous beneficial responses.

For example, research suggests that, when released into nerve tissues, nitric oxide acts to reduce pain.16 In addition, it is thought to act indirectly in the body to inhibit inflammation.17

Nitric oxide is also known to play a critical role in increasing the flow of blood into body tissues. Better blood flow serves to bring fresh nutrients and oxygen into the injured area and remove bacteria and toxins out of it.

Light Therapy for Sore Joints & Muscles
Light Therapy for Sore Joints & Muscles

Incomparable. Invisible. Infrared.

Light consists of different wavelengths within nature’s electromagnetic spectrum.  Some of these wavelengths we can see, such as sunlight, and others we can’t see, such as ultraviolet and infrared light. A wavelength measures light spatially in billionths of a meter, a unit called a nanometer (nm). Medical researchers have studied many wavelengths of light. They have found that different wavelengths work best for treating different conditions. For example, visible and ultraviolet light is absorbed in the skin, so these wavelengths are often used to treat skin conditions such as acne. For treating pain and LumiWave LED podinjury, however, the research shows that the best wavelengths to use are infrared, specifically the narrower wavelengths in the near infrared (NIR) band centering around 900 nm.18-20 Infrared light cannot be seen by the eye. However, unlike visible light or invisible ultraviolet light, infrared light penetrates much more deeply into the body where it stimulates biological processes for pain relief and tissue repair.21,22 Lasers and light-emitting diodes (LEDs) are the standard sources of light used for delivering a controlled amount of infrared light energy to safely penetrate and treat the deeper body tissues.

Shining the Light on Pain Relief

The modern era of using light to treat pain and injury began in the 1960’s with the invention of low-level lasers. Unlike surgical lasers that deliver concentrated beams of energy to cut tissue, low-level lasers produce lower power and deliver lower levels of light in visible, ultraviolet and infrared wavelengths.

LEDs Now a Safer Alternative

Light-emitting diodes (LEDs) were also invented in the 1960’s. These semiconductor light sources were first used as components in electronic equipment, such as for indicator lights. Then scientists began to study them as a way to deliver the same wavelengths of light as lasers and for the same medical purposes.

One important research finding was that, when equally configured, infrared laser and infrared LED light produce the same biostimulating effect on body tissues.23

Today, many medical-grade light therapy devices, such as the LumiWave® device, use infrared LEDs instead of infrared lasers as their source of light. Besides delivering the same therapeutic effect in the body, LEDs offer several important benefits. They are a safer and less expensive technology than lasers. They are also more convenient to use at home because you don’t need to wear protective eyewear.

Research also dictates the proper number of infrared LEDs to use. Medical-grade systems like the LumiWave® device contain in the neighborhood of 200 to 400 LEDs in their technical specifications. It takes at least this approximate number of LEDs to deliver the optimal infrared wavelength and energy dose required to effectively relieve pain.24

References
1 Basford JR, Sheffield CG, Harmsen WS. Laser therapy: a randomized, controlled trial of the effects of low-intensity Nd:YAG laser irradiation on musculoskeletal back pain.  Arch Phys Med Rehab 1999; 80:647-652.

2 Glasgow PD, et al. Low intensity monochromatic infrared therapy: a preliminary study of the effects of a novel treatment unit upon experimental muscle soreness. Lasers in Surg Med 2001; 28: 33-39.

3 Simunovic Z, Ivankovich AD, Depolo A. Wound healing of animal and human body sport and traffic injuries using low-level laser therapy treatment: a randomized clinical study of seventy-four patients with control group. J Clin Laser Med Surg 2000; 18: 67-73

4 Simunovic Z, Trobonjaca T, Trobonojaca Z. Treatment of medial and lateral epicondylitis – tennis and golfer elbow – with low level laser therapy: a multicenter double-blind, placebo-controlled clinical study on 324 patients. J Clin Laser Med Surg 1998; 16: 145-151.

5 Simunovic Z. Low level laser therapy with trigger points technique: a clinical study on 243 patients.  J Clin Laser Med Surg 1996; 14: 163-167.

6 Soriano F. The analgesic effect of 904 nm gallium arsenide semiconductor low level laser therapy on osteoarticular pain: a report of 938 irradiated patients. Laser Therapy 1995; 7: 75-80.

7 Strupinska E. Low-power laser therapy used in tendon damage. Proc SPIE (Lasers in Medicine) 1996; 2781: 177-183.

8 Whelan HT, et al. Effect of NASA light-emitting diode irradiation on wound healing. J Clin Laser Med Surg 2001; 19: 305-314.

9 Bjordal JM, et al. A systematic review of low level laser therapy with location-specific doses for pain from chronic joint disorders. Aust J Physiother 2003; 49 (2): 107-116.

10 Gur, et al. Efficacy of different therapy regimes of low-power laser in painful osteoarthritis of the knee: a double-blind and randomized-controlled trial. Lasers in Surg Med. 2003; 33: 330-338.

11 Ozdemir F, Birtane M, Kokino S. The clinical efficacy of low-power laser therapy on pain and function in cervical osteoarthritis. Clin Rheumatol 2001; 20 (3): 181-184.

12 Tsuchiya K, et al. Diode laser irradiation selectively diminishes slow component of axonal volleys to dorsal roots from the saphenous nerve in the rat. Neurosci Lett 1993; 161: 65-68.

13 Wakabyahsi H, et al. Effect of irradiation by semiconductor laser on responses evoked in trigeminal caudal neurons by tooth pulp stimulation. Lasers in Surg Med. 1993; 13: 605-610.

14 Ohno T. Pain suppressive effect of low power laser irradiation: a quantitative analysis of substance P in the rat spinal dorsal root ganglion.  J Jap Med School 1997; 64: 395-400.

15 Mochizuki-Oda N, et al. Effects of near-infrared laser irradiation on adenosine triphosphate and adenosine diphosphate contents of rat brain tissue. Neurosci Lett 2002; 323: 207-210.

16 Mrowiec J, et al. Involvement of nitric oxide in the mechanism of analgesic effect of ELF magnetic fields in rats. Pol J Med Phys Eng 2001; 7 (1): 3-10.

17 Tidball JG. Inflammatory processes in muscle injury and repair. Am J Physiol Regul Integr Comp Physiol Feb 2001; 288 (2): R345-353.

18 Kujawa J, et al. Effect of low-intensity (3.75-25 J/cm2) near-infrared (810 nm) laser radiation on red blood cell ATPase activities and membrane structure. J Clin Laser Med Surg. 2004 Apr; 22 (2):111-117.

19 Bjordal JM, et al. A systematic review of low level laser therapy with location-specific doses for pain from chronic joint disorders. Aust J Physiother 2003; 49 (2): 107-116.

20 Abergel RP, et al. Biostimulation of wound healing by lasers: experimental approaches in animal models and in fibroblast cultures. J Dermatol Surg Oncol 1987 Feb; 13 (2):127–133.

21 Woodard HQ, White DR. The composition of body tissue. Br J Radiol 1986; 59: 1209-1219.

22 Horecker BL. The absorption spectra of hemoglobin and its derivatives in the visible and near infrared regions. J Biol Chem 1943; 148: 173-183.

23 Basford JR. Low-energy laser therapy: controversies and new research findings. Lasers in Surg Med 1989; 9: 1-5.

24 Romanczyk T, et al.  Dose and intensity dependent effects on normal human neural progenitor cells using 810-nm low-power laser. SPIE Photonics West 2007: Abstract 6428-22, Session 4. https://spie.org/Documents/ConferencesExhibitions/BiOS07-Abstracts.pdf.